Method and apparatus for accommodating higher order modulation in wireless communication

ABSTRACT

A method and apparatus for reconfiguring a wireless transmit/receive unit (WTRU) are directed to receiving an active set update message indicating that a mode of operation allowing a certain modulation scheme is enabled or disabled and performing at least one of: performing a MAC reset procedure, updating a set of reference enhanced transport format combination indicators (E-TFCIs) and associated power offsets, determining actions related to E-DPCCH boosting, modifying information related to an enhanced dedicated channel (E-DCH), and modifying an index that indicates an E-DCH transport block size table. The update message includes at least one modified information element (IE).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/449,548, filed Apr. 18, 2012; which is a continuation of U.S. patentapplication Ser. No.12/191,115, filed Aug. 13, 2008, now U.S. Pat. No.8,233,451; which claims the benefit of U.S. Provisional Application No.60/955,527, filed on Aug. 13, 2007, the contents of which are herebyincorporated by reference herein.

FIELD OF INVENTION

This application is related to wireless communications.

BACKGROUND

Higher-order modulation for the uplink (UL) has been introduced for somewireless communication networks. One example is Release 7 of the HighSpeed Packet Access (HSPA) specifications. In these specifications, forexample, a user equipment (UE) may operate (or not) in the 16-symbolquadrature amplitude modulation (16QAM) mode. When the UE operates inthe 16QAM mode, it has to utilize one of several newly defined enhanceddedicated channel (E-DCH) transport block tables appropriate fortransmitting at data rates up to the maximum rates allowed by 16QAMoperation. When the UE does not operate in the 16QAM mode, it has toutilize one of the original E-DCH transport block tables.

In practical deployments, not all cells of a radio network arenecessarily upgraded at the same time to support a new feature such as16QAM operation. Therefore, it is likely that in initial deployment,some cells in the network will support the feature and other will not.As the UE moves within the network, it will have to add cells to andremove cells from its active set that may or may not support 16QAMoperation. A cell that supports 16QAM operation can properly receivesignals from a UE not operating in 16QAM mode. However, a cell notsupporting 16QAM operation can not properly receive signals from a UEoperating in 16QAM mode. For this reason, a modification to the activeset update procedure has been introduced whereby the network can signalto the UE whether it should start or stop 16QAM operation. The networkwould typically signal to the UE to stop 16QAM operation when a cell notsupporting 16QAM operation is added to the active set, and may signal tothe UE to start 16QAM operation when all cells in its active set supportit.

Although this modification allows the network to signal the start orstop of 16QAM operation to the UE, the UE still does not have all theinformation it needs to properly switch between the two modes ofoperation. When switching operation, the UE cannot use some E-DCHconfiguration parameters as they are currently defined.

Additionally, when these parameters are changed, the enhanced mediaaccess control (MAC-e) needs to flush the UL hybrid automatic repeatrequest (HARQ) buffers which contain MAC-e PDUs with the old enhancedtransport format combination index (E-TFCI) tables.

However, the current active set update procedure does not have anyprovisions to change the above mentioned E-DCH configuration parameters.Some of the parameters, such as E-DPCCH/DPCCH power offset and ReferenceE-TFCI, may be changed with the active set update but only when aserving E-DCH cell change occurs. However, starting and stopping of16QAM operations may also occur when adding a new cell to the E-DCHactive set without changing the serving cell.

The absence of this signaling in the active set update procedureprevents proper transitioning between 16QAM mode and non-16QAM (normal)mode when a cell is added or removed from the (E-DCH) active set or whenthe E-DCH serving cell is modified. By providing the mechanisms forproper transition between 16QAM mode and non-16QAM mode resulting froman active set update procedure, the embodiments to be described hereinallow a reduction in re-configuration delays and a reduction ofsignaling overhead (power and bandwidth).

SUMMARY

A method and apparatus are disclosed for reconfiguring a wirelesstransmit/receive unit (WTRU). The method comprises receiving an activeset update message indicating that a mode of operation allowing acertain modulation scheme is enabled or disabled; and performing atleast one of: performing a MAC reset procedure, updating a set ofreference enhanced transport format combination indicators (E-TFCIs) andassociated power offsets, determining actions related to E-DPCCHboosting, modifying information related to an enhanced dedicated channel(E-DCH), and modifying an index that indicates an E-DCH transport blocksize table. The update message includes at least one modifiedinformation element (IE).

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1 shows a signaling diagram for an active set update message forhigher order modulation.

FIG. 2 is a block diagram of an embodiment of a wirelesstransmit/receive unit (WTRU).

FIGS. 3A and 3B are a flowchart of an embodiment of a method forreconfiguring a WTRU in response to an update message.

DETAILED DESCRIPTION

When referred to hereafter, the terminology “wireless transmit/receiveunit (WTRU)” includes but is not limited to a user equipment (UE), amobile station, a fixed or mobile subscriber unit, a pager, a cellulartelephone, a personal digital assistant (PDA), a computer, or any othertype of user device capable of operating in a wireless environment. Whenreferred to hereafter, the terminology “base station” includes but isnot limited to a Node-B, a site controller, an access point (AP), or anyother type of interfacing device capable of operating in a wirelessenvironment.

A method and wireless transmit/receive unit (WTRU) are disclosed thatenable re-configuring E-DCH transmission parameters when 16QAMoperations are started or stopped following an active set updateprocedure.

FIG. 1 is an example of a signaling diagram which summarizes eventsoccurring as a WTRU moves between cells which employ differentmodulation modes for communication. As a specific example, FIG. 1 showsa case where a WTRU moves from a cell in which 16QAM modulation isavailable toward a cell where this modulation scheme is not available.In FIG. 1, time progresses from top to bottom. Four vertical linesindicate status of four entities: the WTRU 105, a Node B 110 notproviding 16QAM, a Node B 115 providing 16QAM, and a radio networkcontroller (RNC) 120 interacting with both Node Bs 110 and 115.Horizontal arrows show interactions between these entities.

At time 125 the WTRU is operating using 16QAM in communication with NodeB 115. At time 130 the RNC senses that the WTRU is approaching the cellof Node B 110 which does not provide 16QAM. The RNC transmits an activeset update message to the WTRU at time 130 for the purpose of updatingan active set in the WTRU. The active set determines with which cellsthe WTRU can properly communicate. The WTRU receives the message andresponds to it at time 140 by reconfiguring itself so that it cancommunicate with Node B 110 without using 16QAM since, Node B 110 doesnot support this particular modulation scheme. At time 135 the updatingof the active set and reconfiguring of the WTRU is complete.

FIGS. 3A and 3B show an embodiment of a method for reconfiguring a WTRUin response to receiving an update message. The update message maycontain newly defined information elements (IEs) for controlling updateprocedures. The WTRU acts on these IEs if certain conditions are met.

The active set update message is received at 300. The update proceduremay include resetting a media access control (MAC), updating a set ofreference enhanced transport format combination indicators (E-TFCIs) andassociated power offsets, modifying information related to a dedicatedchannel (DCH), and modifying an index that indicates a transport blocksize table. Each of these will now be described in detail. The WTRU isassumed to be communicating within a wireless network.

First to be described is the procedure of resetting a MAC. In order toclear the buffers and start using the new E-DCH configuration, aMAC-es/e reset may be performed during the active set update procedurewhen a change of available modulation occurs, such as from 16QAM beingavailable to not being available or vice-versa. This may be described asa change from 16QAM mode to non-16QAM mode or vice-versa. The networksignals the WTRU through an information element (IE) included in theactive set update message. The IE is included if MAC-es/e reset is to beperformed. The WTRU may receive the message with this IE at 300. Thisparticular IE may be included in the active set update message itself.It may be included in the root of the message or within an alreadyincluded IE, such as an E-DCH reconfiguration info IE, or somewherewithin the branching (“arborescence”) of included IEs, or in a newlyintroduced group of IEs that are present when the WTRU supports, forexample, 16QAM. The latter case is shown in FIG. 3A, and an example of anewly introduced IE designated UL 16QAM Configuration is shown in 310.Details of the UL 16QAM Configuration IE and its included sub-IEs arepresented in Table 4 below.

Referring to FIG. 3A, the WTRU checks the active set update message,received at 300, for the presence of the UL 16QAM Configuration IE, 310.If the UL 16QAM Configuration IE is not included in the message at 310and if the WTRU is operating in 16QAM modulation mode, the WTRU behavioris unspecified, 305.

If the UL 16QAM Configuration IE is present, the WTRU checks if this IEincludes a MAC-es/e reset indicator, 315. If this reset indicator ispresent the WTRU performs a reset of MAC-es/e entity, 330. The reset maybe performed according to the standard 3GPP TS 25.321, version 7.5.0 orlater. If the reset indicator is not present and the WTRU starts orstops 16QAM mode operation, the WTRU behavior is unspecified, 325.

If the UL 16QAM Configuration IE is found to be included in 310 but thisIE does not include an IE called UL 16QAM Settings, an indication may besent to lower layers in the WTRU to stop any operation in 16QAM mode,320.

Alternatively, the WTRU may perform a MAC-es/e reset if the UL 16QAMConfiguration IE is present, and may not perform a MAC-es/e reset ifthis IE is not present.

Alternatively, the WTRU may perform MAC-es/e reset if 16QAM modeoperation is started or stopped.

Next to be described is updating a set of reference enhanced transportformat combination indicators (E-TFCIs) and associated power offsets. Ingeneral, a TFCI allows receiving layers to identify a currently validTransport Format Combination and hence enables a receiver to decode,de-multiplex and deliver received data. The WTRU may update referenceE-TFCIs and associated power offsets even if the E-DCH serving cell isnot changed by the active set update procedure. When 16QAM mode isstarted or stopped, the reference E-TFCI and associated power offsetsare updated accordingly.

Again, new IEs may be defined for this purpose. These IEs, referred toin the following description, are described in Tables 1-4 below.Referring to FIG. 3B and Tables 1-4, if the E-TFCI Boost IE is includedanywhere in the active set update message at 300, this IE is acted upon,350. If the E-DPCCH/DPCCH Power Offset IE is included anywhere in theactive set update message at 300, this IE is acted upon, 360. If theReference E-TFCIs IE is included anywhere in the active set updatemessage at 300, this IE is acted upon, and any sub-IEs in it are actedupon 355. If the E-TFCI Boost IE and Reference E-TFCIs IE are bothincluded in the update message (350 and 355), and if a reference E-TFCIhas a value less than or equal to a value of the E-TFCI Boost IE, and ifthe Reference E-TFCI PO has a value equal to one or more predeterminedvalues, then the behavior of the WTRU is left unspecified 365. In theparticular example of Tables 2 and 3, the predetermined values used forboth reference E-TFCI PO IEs are 30 and 31.

Note that this Reference E-TFCI PO IE is distinct from an existing IE ofthe same name within the E-DCH reconfiguration information IE (Table 2).The two Reference E-TFCI PO IEs may contain the same information butshould never be present simultaneously.

Again, the IEs may be present in the active set update message itself.Alternatively, they may be included in the root of the message or in oneof the included IEs, or somewhere within the branching of included IEs.The WTRU starts using the new IEs at the activation time. If the new IEis not included the WTRU may keep using an existing reference E-TFCI andpower offsets with the indices now pointing to the new E-DCH TransportBlock Size table. Alternatively, if the new IE is not included, the WTRUbehavior is unspecified. Other parameters that are not listed above mayneed to be modified when 16QAM operations are started or stopped. Thismay be achieved by the same or similar method as that described above.

Next to be described is modifying an index that indicates a transportblock size. In current specifications, there are two sets of E-DCHTransport Block Size tables specified for 2 ms transport time interval(TTI): two tables (2 ms TTI E-DCH Transport Block Size Table 0 and 1)for QPSK operations and two tables for 16QAM operations (2 ms TTI E-DCHTransport Block Size Table 2 and 3). Referring to FIG. 3B, the WTRUreceives the table index 0 or 1 in the E-DCH Transport Block Size tableindex IE 370 which, in turn, is contained in the active set updatemessage, 300. If the WTRU is operating in 16QAM mode the WTRUautomatically adds 2 to the table index, thereby indicating that the16QAM tables are to be used, 375. In this case, indices in theScheduling Grant (SG) table may refer to Scheduling Grant Table 2 in thestandard 3GPP TS 25.321, version 7.5.0 or later.

It may be desirable to change the E-DCH Transport Block Size table indexduring an active set update procedure resulting in a change of 16QAMoperations, an operation that is not possible in current specifications.

Various alternatives may be implemented, each alternative affectingwhere the above procedures get executed in the active set updateprocedure—that is, where in the active set update message the IEs arelocated relative to existing IEs.

In a first alternative, IEs may be added as part of the E-DCHreconfiguration information IE. Specifically, IEs for the MAC es/e resetindicator and E-TFCI boost may be added to the E-DCH RL Info new servingcell sub IE, and IEs for E-DPCCH/DPCCH power offset and ReferenceE-TFCIs and its related sub IEs may be added to the E-DCH RL Info othercells IE.

In a second alternative, the added IEs above are added as part of theE-DCH reconfiguration information IE. The difference in this alternativeis that the IEs MAC es/e reset indicator, E-TFCI boost, and E-TFCIBetaED Switch above are added to the root of the E-DCH reconfigurationinformation, while the other IEs for E-DPCCH/DPCCH power offset andReference E-TFCIs and its related sub IEs are added under the E-DCH RLInfo other cells sub IE.

In a third alternative, an E-DCH Info IE is added to the active setupdate message, optionally adding conditions to ensure no ambiguityresults from having the same IE repeated at different places within theactive set update message branching.

In a fourth alternative, a new IE is created that contains all other newIEs and is added to the active set update message. This IE may always bepresent, or it may be present only if 16QAM is supported by the UE, oronly present if the 16QAM operation is stopped or started.

FIG. 2 shows an embodiment of a WTRU 200 configured for implementing themethods described above. WTRU 200 includes a radio resource control(RRC) unit 210 in communication with a Media Access Control (MAC) unit220 and with a physical layer (PHY) unit 230. Physical layer unit 230may embody the Layer 1 (L1) known in certain models of wirelesscommunications.

RRC unit 210 receives an update message. The message may come from aradio network controller (RNC, not shown in FIG. 2) such as feature 120in FIG. 1. RRC unit 210 processes the message and responds byinteracting with MAC unit 220 and PHY unit 230 to reconfigure WTRU 200in response to the message, according to the method described above.

Tables 1-4 show details of new and modified IEs according to the abovedescriptions.

Active Set Update

TABLE 1 Information Type and Semantics Element/Group name Need Multireference description Version . . . . . . . . . . . . . . . . . . UL16QAM configuration OP UL 16QAM REL-7 configuration 10.3.6.69c E-DCHreconfiguration OP E-DCH This IE is not present REL-7 information sameserving reconfiguration if the serving E-DCH cell information cell ischanged with same this message. serving cell 10.3.6.69b E-TFCI boost OPInteger E-TFCI threshold REL-7 (0 . . . 127) beyond which boosting of E-DPCCH is enabled E-TFCI BetaED Switch OP Enumerated E-TFCI thresholdREL-7 (etfci-0, etfci- used for the 128) computation of the gain factorβ_(ed) according to 3GPP TS 25.214 . . . . . . . . . . . . . . . . . .

E-DCH Reconfiguration Information

TABLE 2 Information Element/ Type and Semantics Group name Need Multireference description Version . . . . . . . . . . . . . . . . .. >>Reference MP Integer Refer to REL-6 E-TFCI PO (0 . . . 29)quantization of the power offset in 3GPP TS 25.213 (30, 31) Values 30and 31 REL-7 are only used for E-TFCI > ETFCI Boost . . . . . . . . . .. . . . . . . .

E-DCH Reconfiguration Information Same Serving Cell

TABLE 3 Information Element/Group Type and Semantics name Need Multireference description Version E-DPCCH/DPCCH power offset OP Integer ThisIE is not REL-7 (0 . . . 8) present if the serving E-DCH cell is changedwith this message. Refer to quantization of the power offset in 3GPP TS25.213 Reference E-TFCIs OP 1 to 8 This IE is not REL-7 present if theserving E-DCH cell is changed with this message. See 3GPP TS25.214. >Reference E-TFCI MP Integer REL-7 (0 . . . 127) >ReferenceE-TFCI PO MP Integer Refer to REL-7 (0 . . . 29) quantization of thepower offset in 3GPP TS 25.213 (30, 31) Values 30 and 31 REL-7 are onlyused for E-TFCI > ETFCI Boost

UL 16QAM Configuration

TABLE 4 Information Element/ Type and Semantics Group name Need Multireference description Version UL 16QAM settings OP UL 16QAM Presence ofthis REL-7 settings IE indicates that 10.3.6.86a the UE should operatein 16 QAM mode; absence indicates that the UE is not to operate in 16QAM mode. MAC-es/e reset indicator OP Enumerated TRUE Indicates REL-7(true) the MAC-es/e entity needs to be reset. E-TFCI table index OPInteger (0 . . . 1) Indicates which REL-7 standardised E- TFCI TB sizetable shall be used. See Note 1. NOTE 1: If the UE is operating in 16QAM mode, the value of “E-TFCI table index” is increased by 2, andindices in the SG-Table refer to Scheduling Grant Table 2 in [15].

Although features and elements are described above in particularcombinations, each feature or element can be used alone without theother features and elements or in various combinations with or withoutother features and elements. The methods or flow charts provided hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) or Ultra Wide Band (UWB)module.

What is claimed is:
 1. A method for reconfiguring a wirelesstransmit/receive unit (WTRU) via an active set update message, themethod comprising: sending the active set update message comprising amodulation mode information element (IE), the modulation mode IEindicating whether to operate in a modulation mode; and determiningwhether to include a media access control (MAC) reset IE in themodulation mode IE, wherein an inclusion of the MAC reset IE indicatesto reset a MAC entity.
 2. The method of claim 1, further comprisingdetermining whether to include an enhanced dedicated channel (E-DCH)transport format combinations indicator (E-TFCI) table index IE in themodulation mode IE, wherein an inclusion of the E-TFCI table index IEindicates which E-TFCI transport block size table to use.
 3. The methodof claim 1, wherein the modulation mode is 16-symbol quadratureamplitude modulation (16QAM).
 4. The method of claim 1, wherein theactive set update message comprises information enabling the WTRU toupdate an active set which indicates active cells available to the WTRUfor communication.
 5. The method of claim 1, further comprisingdetermining whether to include an enhanced dedicated physical controlchannel (E-DPCCH)/DPCCH power offset IE in the active set updatemessage, wherein an inclusion of the E-DPCCH/DPCCH power offset IEindicates whether to modify a power offset of an E-DPCCH/DPCCH.
 6. Themethod of claim 1, further comprising determining whether to include areference enhanced dedicated channel (E-DCH) transport formatcombinations indicator (E-TFCI) power offset IE in the active set updatemessage, wherein an inclusion of the reference E-TFCI power offset IEindicates whether to modify a power offset of the reference E-TFCI. 7.The method of claim 1, further comprising determining whether to includean enhanced dedicated channel (E-DCH) transport format combinationsindicator (E-TFCI) Boost IE in the active set update message, whereinthe E-TFCI Boost IE indicates whether to modify an E-TFCI threshold. 8.The method of claim 7, wherein boosting of an enhanced dedicatedphysical control channel (E-DPCCH) is enabled on a condition that anE-TFCI value exceeds the E-TFCI threshold.
 9. A network entitycomprising: a processor configured to: send an active set update messagethat includes a modulation mode information element (IE), the modulationmode IE indicating whether to operate in a modulation mode; anddetermine whether to include a media access control (MAC) reset IE inthe modulation mode IE, wherein an inclusion of the MAC reset IEindicates to reset a MAC entity.
 10. The network entity of claim 9,wherein the processor is further configured to determine whether toinclude an enhanced dedicated channel (E-DCH) transport formatcombinations indicator (E-TFCI) table index IE in the modulation modeIE, wherein an inclusion of the E-TFCI table index IE indicates whichE-TFCI transport block size table to use.
 11. The network entity ofclaim 9, wherein the modulation mode is 16-symbol quadrature amplitudemodulation (16QAM).
 12. The network entity of claim 9, wherein theactive set update message comprises information enabling the WTRU toupdate an active set which indicates active cells available to the WTRUfor communication.
 13. The network entity of claim 9, wherein theprocessor is further configured to determine whether to include anenhanced dedicated physical control channel (E-DPCCH)/DPCCH power offsetIE in the active set update message, wherein an inclusion of theE-DPCCH/DPCCH power offset IE indicates whether to modify a power offsetof an E-DPCCH/DPCCH.
 14. The network entity of claim 9, wherein theprocessor is further configured to determine whether to include areference enhanced dedicated channel (E-DCH) transport formatcombinations indicator (E-TFCI) power offset IE in the active set updatemessage, wherein an inclusion of the reference E-TFCI power offset IEindicates whether to modify a power offset of the reference E-TFCI. 15.The network entity of claim 9, wherein the processor is furtherconfigured to determine whether to include an enhanced dedicated channel(E-DCH) transport format combinations indicator (E-TFCI) Boost IE in theactive set update message, wherein the E-TFCI Boost IE indicates whetherto modify an E-TFCI threshold.
 16. The network entity of claim 15,wherein boosting of an enhanced dedicated physical control channel(E-DPCCH) is enabled on a condition that an E-TFCI value exceeds theE-TFCI threshold.
 17. A method for a wireless transmit/receive unit(WTRU) to act upon receiving an active set update message, the methodcomprising: receiving the active set update message indicating whetherto operate in a modulation mode via a modulation mode informationelement (IE); in response to the active set update message, indicatingto one or more lower layers to operate in or stop the modulation mode;and determining whether to perform a media access control (MAC) resetprocedure based on whether a MAC reset IE is included in the modulationmode IE.
 18. The method of claim 17, further comprising determining anenhanced dedicated channel (E-DCH) transport format combinationsindicator (E-TFCI) transport block size table based on whether an E-TFCItable index IE is included in the modulation mode IE.
 19. The method ofclaim 18, wherein the determining comprises: identifying the E-TFCItransport block size table based on a value of the E-TFCI table index IEincreased by 2 on a condition that the WTRU is operating in a 16-symbolquadrature amplitude modulation (16QAM) mode.
 20. The method of claim18, wherein determining the E-TFCI transport block size table comprises:using an E-TFCI transport block size table indicated by the E-TFCI tableindex IE on a condition that the E-TFCI table index IE is included; andusing an E-TFCI transport block size table indicated by a previous indexon a condition that the E-TFCI table index IE is not included.
 21. Themethod of claim 17, further comprising: on a condition that the MACreset IE is included in the modulation mode IE, performing the MAC resetprocedure.
 22. The method of claim 17, wherein an inclusion of themodulation mode IE indicates to operate in the modulation mode, and anabsence of the modulation mode IE indicates not to operate in themodulation mode.
 23. The method of claim 17, wherein the modulation modeis 16-symbol quadrature amplitude modulation (16QAM).
 24. The method ofclaim 17, wherein the active set update message comprises informationenabling the WTRU to update an active set which indicates active cellsavailable to the WTRU for communication.
 25. A wireless transmit/receiveunit (WTRU) comprising: a processor configured to: receive an active setupdate message indicating whether to operate in a modulation mode via amodulation mode information element (IE); indicate to one or more lowerlayers to operate in or stop the modulation mode; and determine whetherto perform a media access control (MAC) reset procedure based on whethera MAC reset IE is included in the modulation mode IE.
 26. The WTRU ofclaim 25, wherein the processor is further configured to determine anenhanced dedicated channel (E-DCH) transport format combinationsindicator (E-TFCI) transport block size table based on whether an E-TFCItable index IE is included in the modulation mode IE.
 27. The WTRU ofclaim 26, wherein the processor is further configured to use an E-TFCItransport block size table indicated by the E-TFCI table index IE on acondition that the E-TFCI table index IE is included, and use an E-DCHtransport block size table indicated by a previous index on a conditionthat the E-TFCI table index IE is not included.
 28. The WTRU of claim25, wherein the processor is further configured to perform the MAC resetprocedure on a condition that the MAC reset IE is included.
 29. The WTRUof claim 25, wherein the processor is configured to operate in themodulation mode on a condition that the modulation mode IE is includedin the active set update message, and stop operating in the modulationmode on a condition that the modulation mode IE is not included in theactive set update message.
 30. The WTRU of claim 25, wherein themodulation mode is 16-symbol quadrature amplitude modulation (16QAM).